In spectroscopy, so-called spectroscopic apparatuses are frequently used for detecting/measuring the spectrum of electromagnetic radiation, in particular in the spectral ranges ultraviolet (UV), visible (VIS) and infrared (IR). Here, the dispersive element needed for splitting the electromagnetic radiation is frequently configured as diffraction grating. New applications where spectroanalytical measurements play an important part, such as environmental measurement technology and food analysis need small, robust and cost-effective spectroscopic apparatuses, possibly in very large quantities. Here, it has to be considered that some of these applications call for powerful devices, comparable to commercially available compact spectrometers. As one example, the spectral resolution of such devices of 10 nm half width in the near infrared spectral range of 1000 nm to 1900 nm is stated.
The above-stated requirements cannot all be fulfilled at the same time with conventional technology. The three issues small structural size, low cost and large quantities at least partially contradict each other. With constant device performance, miniaturization results in complex components and/or assembly processes. This increasing complexity again causes increased production costs which may have a negative effect on the production of very large quantities. Solutions that can be produced at low cost in large quantities do not reach the requested performance.
MEMS-based spectrometers are known from conventional technology. MEMS spectrometers mean embodiments that are provided with a movable diffraction grating. These devices are produced in respective microtechnology and have an integrated drive for deflecting a grating mirror plate. With the selection of a suitable material system, e.g., silicon and the matching drive type, e.g., electrostatic, deflectable diffraction gratings having a large deflection amplitude can be produced, which are particularly well suited for the design of miniaturized spectroscopic apparatuses. A detailed description of such systems can be found in U.S. Pat. No. 8,045,159 B2 about hybrid spectrometers.
Laboratory and compact spectrometers are already known. These are, among others, Czerny-Turner spectrometers/spectrographs as standard and crossed variation. Further, MEMS grating spectrometers in stacked design with complex optical members are known which can, among others, be produced in a miniaturized manner.
For miniaturized and precise spectrometers, very small inlet openings and outlet openings might be needed. MEMS gaps in different substrate configurations are known.
In view of the above, there is a need for a concept allowing an improved tradeoff between reducing the structural size, reducing the cost as well as producing spectroscopic apparatuses in large quantities. Thus, a miniaturized spectroscopic apparatus comprising, for example, all the above-stated features is to be provided.